Conventional office chairs are designed to provide significant levels of comfort and adjustability. Such chairs typically include a base which supports a tilt control assembly to which a seat assembly and back assembly are movably interconnected. The tilt control mechanism includes a back upright which extends rearwardly and upwardly and supports the back assembly rearwardly adjacent to the seat assembly. The tilt control mechanism serves to interconnect the seat and back assemblies so that they may tilt rearwardly together in response to movements by the chair occupant and possibly to permit limited forward tilting of the seat and back. Further, such chairs typically permit the back to also move relative to the seat during such rearward tilting.
In addition to supporting the seat and back of the occupant, the chair also may include support assemblies that support the occupant's body at various locations thereof. One primary support assembly of this type is an arm assembly wherein an arm assembly is mounted on each opposite side of the seat so as to support the arms and specifically, the elbows and forearms of the occupant. Such arm assemblies project upwardly and include an upward facing armrest thereon which armrest defines a support surface to accommodate the occupant's arms.
However, one difficulty associated with the design of conventional office chairs is the fact that office workers have different physical characteristics and comfort preferences such that it is difficult to design a single chair configuration that satisfies the preferences of the different individuals who might purchase such a chair.
To accommodate these differences, it is known to provide arm assemblies which allow for adjustment of the height of the armrest as well as the relative location of the armrest relative to the seat assembly. An armrest therefore may be movable in its angular orientation as well as its position in the front-to-back direction as well as the side-to-side direction.
In view of the foregoing, it is an object of the invention to provide an improved arm rest assembly which allows ready configurability thereof while providing improved comfort with respect to the range and combination of motions which are permitted.
The invention relates to an arm assembly which not only is height adjustable but also permits adjustment of the armrest in the angular, front-to-back and sideward directions. This arm assembly includes a support post mounted to the base of the chair and preferably, the upright thereof so that the armrest moves in unison with the upright during tilting of the chair and maintains the arms in a proper orientation relative to the seat and back of the user when reclining.
To provide this height-adjustability, the arm assembly includes an armrest assembly having a vertically elongate column that projects downwardly and is slidably received within a tubular support post fixed to the chair frame. This support post includes an arrangement of plastic liner sections which fit within the tube and also define vertically spaced apart recesses that correspond to various elevations at which the armrest may be maintained.
To maintain the armrest at such elevations, a latch mechanism is provided which comprises a vertically movable lever disposed within a hollow interior of the armrest column. The latch assembly further includes a cassette assembly which snaps into the side of the column and has a spring-loaded, slidable latch that moves sidewardly into engagement with any of the various recesses located within the post liner. The cassette assembly also engages with the lever and prevents removal thereof.
The armrest provides three directions of movement in addition to height-adjustability. Specifically, the armrest includes a multi-layer plate arrangement wherein multiple layers of plates are stacked one above the other and are each movable horizontally in an associated direction.
More particularly, a first pivot plate is pivotally connected to the armrest column and is maintained in a selected angular position by a first detent. The detent defines multiple angular positions at which the armrest may be maintained while also permitting angular movement of the armrest when the stopping threshold or capacity of the detent is overcome as the occupant manually moves the arm cap at the top of the armrest.
The pivot detent preferably comprises a ring of elastomeric material wherein one sidewall of this ring includes a plurality of angularly spaced recesses that define the various angular positions of the armrest. Deflection of this detent wall therefore permits angular movement and defines the stop capacity of the detent.
Additionally, a second slide plate is mounted on top of the pivot plate and is slidable relative thereto in the front-to-rear direction. A slide detent is fitted within the slide plate wherein this slide detent is fixed to the pivot plate to fasten the slide plate to the pivot plate. The slide detent also selectively restrains the slide plate while also defining a stop threshold above which the slide plate may be moved upon the user's manual application of a suitable force to the arm cap. The slide detent is formed somewhat similar to the pivot detent in that it is a ring of elastomeric material which is deformable. In this case, the slide detent has opposite sidewalls which deflect inwardly.
Furthermore, an upper transverse subcap plate is slidably supported on the intermediate slide plate through a retainer. The subcap plate is sidewardly or transversely slidable while the retainer carries a resiliently deflectable top detent that engages the subcap plate to maintain the subcap plate in a sidewardly adjusted position while defining a stopping threshold above which a force may be applied to the arm cap to permit sideward adjustment thereof.
With this arrangement, the arm cap may be readily adjusted vertically as well as horizontally.
Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.